Plate 4 



Page 

 Figs. 1,2. Membraniporella petastis, new species 36 



1. Ovicelled specimen with smooth costules; X 20. 

 Albatross Station D. 2319, north of Cuba. 



2. The incrusting zoarium showing ancestrular zooecia 



with thickened costules; X 20. 

 Albatross Station D. 2167, off Habana, Cuba. 

 3-8. Cauloramphus opertus, new species. 35 



3. Specimen with ectocyst, covered by its opesial spines; 



X 20. 



4. Same specimen after boiling in Javelle water; X 20. 



5. A zooecium viewed by transparency showing the 



opesium covered with opesial spines; X 50. 



6. View showing structure of pedunculate avicularium; 



X 85. 

 7,8. Views showing structure of distal spines; X 85. 

 Albatross Station D. 2405, Gulf of Mexico. 



9,10. Acanthocella clypeata, new species 39 



9. The broken part of the frontal showing the presence 

 of the ectocyst under the costules and the membran- 

 iporoid structure of the zooecia; X 20. 

 10. A portion of the frontal showing the structure of the 

 costules. The lumen line has much thickened walls; 

 X 85. 

 Albatross Station D. 2373, Gulf of Mexico. 



11. Gephyrotes spinosum, new species 29 



The incrusting zoarium illustrating spinous aspect of sur- 

 face; X 20. 

 Albatross Station D. 2319, north of Cuba. 



12. Halophila johnstoniae Gray, 1843 42 



An ovicelled branch with the ectocyst altered in drying. 

 Albatross Station D. 2405, Gulf of Mexico. 

 13,14. Bugula avicularia Linnaeus, 1758 41 



13. Anterior face; X 20. 



14. Posterior face; X 20. 



Albatross Station 2392, Gulf of Mexico. 



169 



